SwiftFox - S7 Super Sport Build (Vancouver, Canada)

[nathan_s]

Hi all! My name is Nathan, I'm first time builder in Vancouver, Canada and I'm building a S7 Super Sport.

The current plan in summary form is to go with the following:

Engine: Rotax 912iS
Prop: 70inch 3-blade Airmaster (with whirlwind blades)
Gear: Grove Spring Gear with Beringer 8inch wheels and brakes and a T3 Tailwheel
Covering: Stewart Systems
Avionics: Full Garmin suite with a Garmin G3X Touch (10 inch) as the main PFD


The kit arrived on March 25th. I met Brandon and Heather in Bellingham WA and transferred the kit into a rental truck to bring it across the border into Canada.

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I immediately started building a couple of wing rotisseries and a stand for the fuselage to stand on. There was another aircraft in the hangar for the first couple of weeks as it waited to depart for its new home, so I was delayed getting the rotisseries and stand finished due to that. Once that other aircraft was gone, I completed inventory which took just 2 days, and then started on the horizontal stabilizer.

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It's been a few weeks since then, and a lot has been done and learned. The ribs and rib stiffeners are glued into the horizontal stabilizer and elevator, and I'm going to be mounting them into the fuselage next.

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It has been an interesting start to say the least. There's been days when I've been able to get a lot done, and other days where I've spent most of my time just figuring out what I needed to do a particular piece of work; with a lot of trips to hardware stores. It's all part of the experience so I'm not at all demotivated by it. In fact its the opposite, I'm feeling like I'm learning a lot and getting more into a rhythm with each day.

I'm working full time on the build until at least the end of August, and we'll see where we can go from there.

The forums have been a hugely helpful resource thus far. Thank you to everyone who has contributed. I've been following a lot of other build threads and have notes from many of you of ways to do things better, easier, faster, etc. I'm going to be incorporating much of your ideas into my build.

[Kitfox Pilot]

Welcome Nathan!
You are starting an adventure for sure.
There will be times that you wonder why I started this! haha. But in the end it is all worth it.
Teamkitfox is a great place to get lots of the info you will need during the built.
I look forward to watching your build as it progresses. Harlan

[DesertFox4]

Congrats Nathan on your kit delivery and such a good start to the build process. Will be following progress.

[nathan_s]

Thanks, Harlan and DesertFox4. Appreciate the words of support.

Building has been progressing solidly. All of the ribs are bonded and varnished in the horizontal and vertical stabilizers, the elevator, and the rudder. I'm preparing now to bond in the fibreglass fairing onto the vertical stabilizer.

I learned a lot about trimming and bonding the ribs working on the horizontal stabilizer and elevator, and am much happier with the quality of my work in the vertical stabilizer and rudder as a result. The gluing, in particular, looks a lot better! I've been using the applicator gun and cartridges instead of the syringe/ziploc bag methods as I figured it would allow me to go a bit slower and correct more mistakes. It's definitely a nice way to go about gluing.

I've had the horizontal stabilizer mounted into the fuselage, and hooked up to the trim motor. My slider blocks are fitting very snug. So snug I'm a little concerned they might be too tight, and that the trim motor might be taxed in operation. Using a 9V battery, I timed how long it took the motor to move the horizontal from the bottom position (nose up) to top position (nose down), and it was about 21 seconds. Seems like a long time, but it is also only a 9V battery. I'm wondering if others have timed theirs with a 9V battery (or other known voltage) and know what their timing was for a comparison?

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[alexM]

My trim motor is easily accessible so I'll time it with a 9v tomorrow morning. I've tested it with a 12v motorcycle battery and it didn't take anything like 21 seconds but with a simple 9v battery it might.

[nathan_s]

My trim motor is easily accessible so I'll time it with a 9v tomorrow morning. I've tested it with a 12v motorcycle battery and it didn't take anything like 21 seconds but with a simple 9v battery it might.

Thanks, alexM. Appreciate it!

[Geek]

The good news about using a 9V battery to exercise the trim motor is that it works - kinda. The bad news is that the 9V battery has two things working against it; low voltage and low current. With those two issues it's going to be slow. If you are worried that the trim motor has an issue - hook it to a car battery or something with the power to drive it at its rated voltage with enough current. The 9V battery isn't going to give you a good yay or neigh indication.

Geek

[PapuaPilot]

Mine goes full stroke in about 10 seconds with the ship battery, which is around 13 volts.

If you want to know if the slider blocks are too tight time the actuator with the blocks removed or just run the actuator totally disconnected from the stab.

[nathan_s]

Thanks, all.

Phil, I'll definitely try your suggestion when I get out to the hangar later this morning. The horizontal stabilizer is out of the fuselage at the moment so I can pretty easily time the motor on its own.

To elaborate a little on where my concern came from. Before even connecting the trim motor to the horizontal I was worried the slider blocks were too tight. It required a bit of a push to get the slider blocks around the bar in the fuselage, and then to move the horizontal stabilizer up or down, I need to give it a good push or pull depending on the desired direction, and there's no fine control on how far it will travel.

I used the 9V battery mostly as a way to get a repeatable measurement and it was what I had readily available. I might see if I can get my hands on a 12V to be closer to a real-world scenario.

[nathan_s]

Alright, so I'm not much less concerned about the slider blocks being too tight. I tested the motor on its own (not connected to the horizontal stabilizer) using the 9V battery and the travel time is close enough to when the horizontal is attached. I'll retest again when I've got the proper battery, but for now, I'm moving on.

I've got most of the tail section completed now. I still need to do the foam tips, and measure and verify the rudder has 25° of travel. I'm also going to come back prior to covering and clean up some of the transitions so that some lumps and bumps can't be seen through the fabric etc.

On cutting the access holes in the rudder, the diagram in the manual showed quite a large rectangular hole for the bottom one where the rudder stop and rudder horn are. I ended up doing 3 separate holes, sized just for what each are needed for. Not sure if I'll need to just make a single large one later, but this seems to work...?

I saw mention of John (McBean's?) personal airplane having some covers over these access holes. I couldn't find any photos on the forum of them. Does anyone have any details on these, or photos?

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On to what I'm doing next; I'm starting Flight Controls today!

[nathan_s]

It’s been over two months since I posted an update. Apologies, between being back home for a friend’s wedding, then having some family visiting me there has been a lot going on. But there’s been a lot of progress on the Kitfox in between, so let me catch you up on that.

Flight controls are in! This was a bit of a slog, and while rewarding to finally be done, it wasn’t without frustration. The difficulty was mostly centred around mounting the Control Column into the fuselage.

I messed up the control column mounting bracket and column bearing block and had to order some replacement parts to make them again.

On the control column bracket, I made two mistakes. The first was that I pressed in the bushing into the bearing, where the bushing would not spin/turn like it should. I immediately realized my mistake, and it would have been recoverable except for my second mistake which was botching the mounting holes in the bracket.

The first hole I drilled was right up against the inside wall of the bracket so you wouldn’t have been able to get a tool on the head of the bolt. I tried drilling a new hole, but because I had to have it off the centre line of the internal box part of the bracket to give it clearance from the errant hole, it meant that the two mounting holes on the outer side of the bracket were now too close to the outside wall of the bracket.

For the bearing block, I ended up drilling the second mounting hole crooked, which meant the whole block was kinked, and I’d have to remove a lot of material to get the control column to move smoothly.

Basically, my problem was back drilling from the underside of the fuselage. I wasn’t able to get enough force behind me to keep things straight and I think the bracket shifted as I started drilling as I hadn’t gotten it clamped as well as I’d have liked. That’s probably the big downside of having the fuselage mounted in the stand I made; I couldn’t just tip it over on its side to drill.

I ended up ordering new parts from Kitfox to redo it all, and learn from my mistakes. Instead of back drilling into the bracket itself, I back drilled into a piece of scrap plywood and used that as a drill template when drilling into the bracket proper. I found where I wanted the bracket positioned in the fuselage, used a sharpie to mark it, then lined up the plywood template over the markings and drilled. It worked really well.

The second bearing block deformed while drilling the second mounting hole (has it not deformed for anyone?), but the hole was straight through the block this time. I used a drum sander bit in my drill press to remove a lot of material to get the hole in the block back to a circular shape and a clearance fit for the control column.

I had seen a thread on here about someone suggesting using sleeves around the bolts to stop the block from deforming, and I was hoping to go that method, but the tube I received had not been made with tight tolerances and I didn’t have the tooling to correct it so I had to go with the manual’s way in an effort to keep the project moving. It would be nice if this area was improved in the design and fabrication. It probably many days to get everything moving smoothly.

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The centre console is in now too, and I’ve got the detent brackets placed and drilled for riveting. I was a little confused here with regards the instructions for the pre-fab kit parts when it comes to the rivets to use. I had consulted with Brandon on a different part of the instructions earlier and he said they’re a bit out of date so I suspect its the same story with the rivets. Basically the rivets that are specified in the pre-fab instructions didn’t come in the kit (not listed in inventory) and the rivets that are in the manual are too short. I’ve ended up measuring the length of rivets needed and have ordered solid flush head rivets in place of the pop rivets. I’m probably going to paint my centre console the same colour as my panel, and I’d like it to be as smooth as possible, hence the solid flush rivets.

Next I moved onto the door frames and window frames and have just finished bonding and riveting them in. This process was easy enough after watching Aaron Butte’s video (https://www.youtube.com/watch?v=ysEdRO3-Y5o) where he discusses with Brandon how Kitfox does their doors and windows and what tips they have for builders. I’d highly recommend giving this a watch if you’re about to start your doors and window frames, it really helped me understand what to do.

I'm going to start working on the body work for the window and door frames next.

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I’ve been documenting my build on YouTube, mostly for my folks, family, and friends back home, but figure I should post a link here too. It’s not much more info than I’ve already written. Here’s the latest video...


https://youtu.be/c-AJJ9xi7lw

Lastly, I want to give a shout out to Martin. I don’t know if he’s on the forum here, but he flies a Kitfox Model 4 in Clifden in the West of Ireland, and while I was home I had the chance to go out and visit him and see his Kitfox and chat all things flying for a couple of hours. It was great meeting another Kitfox owner and pilot, especially someone from my home county in Ireland. He's got a video on YouTube with him flying around some parts of Ireland and it is stunning https://www.youtube.com/watch?v=aT4CUU0ehXU

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[Kitfox Pilot]

Looks like you got it done right and that's the main thing. Everybody has some redos for sure. Keep posting we enjoys watching people build! Harlan

[nathan_s]

Thanks Harlan!


Sent from my iPhone using Tapatalk

[olsonCCR]

Nathan,
Nice work on your build. I'm building an S7 as well. (Working on my window and door frames now, and am almost ready to start work on my wings). I just watched your video and had the same idea as you, and used flush rivets for the center console in place of the pop rivets in the kit. I really enjoyed the experience having not worked with flush rivets before but keeping the bucking bar in place when using the rivet gun was way more difficult than I thought working in such a tight space. Every time the bucking bar came off I dented the underside of the console which is visible from the top.

Just sharing my experience in case you haven't started with your flush rivets. I should have protected the top surface better and practiced using the rivet gun with the bucking bar more before starting.

I used both a manual squeezer with a 3" yoke, and a rivet gun. The squeezer wouldn't fit in between the bracket and the side of the console as it tapers, which required the rivet gun resulting in the surface denting. Great learning experience but I will definitely need to use some super fill to clean up the surface to prep it for covering. Originally, I thought it would look cool to have the console top and rivets exposed.

In the sun, my finished console looks pretty rough! Inside the plane, not very noticeable but I do still plan to cover it. All in all, I'm pretty happy with the final result.

One other unexpected challenge I had (which I still need to address) was after finishing riveting, the console surface bent ever so slightly near the adjustable rudder handles from the use of the rivet gun, resulting in the handle notch tolerances being slightly too tight when moved from each ratchet position, making the handles difficult to lock. Once I remove the console again, I need to "press up" the console top from the underside a bit, which should solve this issue. Everything works fine and locks in place but it's not perfect.

Anyways, look forward to watching your progress!
Good luck with your build.

Kevin Olson
Building an S7 STi

[nathan_s]

Thanks for that info, Kevin. I'll definitely be keeping it in mind.

My only previous experience with a rivet gun was at AirVenture in 2019 when I attended a Sheet Metal workshop where we riveted a small piece of aluminum sheet to a couple of angle brackets. I might try and find some way to do some more practice before doing it for real on the centre console.

Also I've been following along with your update videos on YouTube. Looks like you're making great progress with your build!

[olsonCCR]

Thanks for that info, Kevin. I'll definitely be keeping it in mind.

My only previous experience with a rivet gun was at AirVenture in 2019 when I attended a Sheet Metal workshop where we riveted a small piece of aluminum sheet to a couple of angle brackets. I might try and find some way to do some more practice before doing it for real on the centre console.

Also I've been following along with your update videos on YouTube. Looks like you're making great progress with your build!

Thanks Nathan. I really enjoy using the rivet gun but am still figuring things out. I'm following your build as well. Look forward to seeing the progress! I'm trying to get more involved on the forum and share my progress but it's been a challenge finding time. Working on my door frames and windows still. I kept putting them off and can't wait to get them finished now!

Keep posting!

Kevin

[nathan_s]

Door and window frames are done! It took a bit longer than expected (isn't everything?), primarily due to a mistake I made which I'll speak to in a moment, and some more family I had visiting, but I'm really happy with where it is at now, and I don't think I can improve it much more with my current Superfil-skill level.

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The mistake I made was a really dumb one, but I've been reassured by a mate a couple of hangars down it is one that everyone makes from time to time. I mixed the SuperFil incorrectly, 1:1, instead of 2:1. This was after I had correctly put a little on some in a couple of places as a test and sanded back to get a feel for how it works. When I was satisfied with that little test I put SuperFil on all the remaining joints, but in the wrong ratio so it never hardened. It ended up being this mess that I had to spend a couple of days scraping off. I've since written "1" and "2" on the tops of the SuperFil containers to remind me in future.

berryP also called out to the hangar one afternoon to see the build, and even applied some Hysol onto the window frame for me. Thanks for the help, berryP!

I've also finished riveting the detent brackets into the center console. Fortunately, I didn't have the same problem as yourself, Kevin. I was a bit worried about it, so I riveted the adjustable rudder pedal brackets first, going from aft to fore. Followed by the flap detent bracket going fore to aft. I thought that way it would be stretching the console if any, instead of bowing it. Not sure if that is a reality, but figured it was a good way to go about it anyway.

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I just published the latest build update video, covering the door and window frames.


https://www.youtube.com/watch?v=hnNtQuGf51U

[nathan_s]

Does this look wrong?

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I'm working on the header tank, and inserting the fittings. I can only twist the fittings in three, maybe four threads before they're getting too tight to go any further. I would expect I need to have these fittings fully in with maybe only a single thread out? Should I pull these out, clean them up and tap the holes again so they go in further?

[jiott]

I would re-tap and then thoroughly deburr and flush the tank. I wouldn't worry about a couple threads showing, but 4 is too much in my opinion. Better yet, the engineering specs on an NPT thread are as follows:

Hand tight thread engagement = 0.1615" for 1/8 npt and 0.2278" for 1/4 npt
Maximum thread engagement = 0.2639" and 0.4018"

Thread engagement is measured from the bottom of the fitting to the top of the female thread on the boss, when wrenched in to proper torque.

[Kitfox Pilot]

[QUOTE=nathan_s;105846]Does this look wrong?

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I had to re tap my header tank and the main fuel tanks to get the right amount of threads in. More threads in= much less chance of a leak.

[nathan_s]

Thanks Jim, Harlan.

I got out to the hangar again this afternoon, and a friend from a couple of hangars down came in to look at them for me too. At first glance he thought they would probably be fine, but after a few minutes more chatting and looking we came to the realization that I had overtightened them. I wasn't aware of the tightening procedure for NPT fittings.

We pulled out the two fittings I had put in, and inspected the threads on the female side and they were a bit off from the overtightening. Nothing that couldn't be fixed by re-tapping I was told, so thankful to have heard that.

I've just ordered a tap, and replacement fittings too, and they should be here by early next week. I'll re-tap all of the holes in the header tank (not just the ones I put the fittings in).

I'm going to shift focus now to installing the auto-pilot servo kits while waiting for everything to arrive.

While I am stalled on continuing to work on the header tank, is there a trick to getting the elbow fittings to point the desired direction when installing them, or is it a trial and error type of thing?

[PapuaPilot]

While I am stalled on continuing to work on the header tank, is there a trick to getting the elbow fittings to point the desired direction when installing them, or is it a trial and error type of thing?

If you have more than one of the same elbow fittings you can do it by trial and error. You should be able to get these fittings tight enough, but not to tight within the one turn limitation. Be sure to use the EZ Lube or other fuel fitting thread sealant. This both seals the fitting and allows it to turn without galling (aluminum galls easily). Start by turning it in by hand till you can't turn it any more, then use a wrench to turn it to the desired orientation. As long as you can't loosen it by hand it should be fine. As a last resort you could tap out the hole another half turn, but I have not found this to be necessary in all of my experience.

[nathan_s]

Thanks Phil. Will try that way.

For the sealant, I'm using Permatex 85420 (https://www.permatex.com/products/gasketing/gasket-sealants/permatex-permashield-fuel-resistant-gasket-dressing-flange-sealant-2-oz/) which was supplied with the kit from Kitfox.

[nathan_s]

NPT tap arrived along with the replacement fittings. One of my hangar neighbours has a lot of automotive maintenance experience, so I asked them to come by to help with the header tank. Figured I could use the experience after messing up the first attempt.

We were able to re-tap the ports (is “port” the right term?) in the header tank, although we didn’t get too many extra turns in from what was already there. The fittings maybe go one, or one and a half more threads in now. According to my neighbour, it is a function of where the taper is in the header tank. If I had longer fittings with more of the bottom end of the taper, or the taper in the port was more towards the bigger side, more threads would go in.

Alas, we’re where we are, and he reckons there is enough in and they won’t leak. I’ll be keeping an eye on it for sure during testing.

We ended up not putting in the elbow fittings permanently yet as he suggested waiting until the fuel lines were being run to make sure they were pointing in the direction I want, so they’re just in there barely hand tight.

Autopilot servos got installed easy enough. The bracket for the pitch servo was warped a bit from the manufacturing process at the factory, so I needed to manipulate it a bit it to have it sit nicely into the fuselage frame. Other than that, it was a straightforward process.

I didn’t put on the cages that protect the servo from going over center. I figured I’d wait until I’ve rigged all the push rods before figuring out where the cage needs to go. I assume rigging of the elevator push rods should happen before covering, as it’ll be awkward getting into the aft of the fuselage to change the rod end lengths?

Trim position sensor kit is also installed. My sensor housing came with a mounting hole pre-drilled in it, and there was also a hole pre-drilled in the tab on the fuselage for it. Using these mounting holes though meant there was about a half inch gap between the sensor switch and the position bracket in the horizontal stabilizer when in the full nose-up trim. I ended up having to drill a new hole in the fuselage tab, and also mount the sensor on the back side of it to make the travel of the sensor switch work.

I’m working on the end caps for all the tail feathers now, because I’m going to be moving hangars at the end of this month and I don’t want to open up any new bags of parts or have loose stuff lying around when I have to move.

I’ve been building in a friends hangar up until now, while waiting for my hangar to complete. It has been delayed a lot due to COVID and other things. It is at a different airport so there’s some logistics involved that I’m not looking forward to, but I’m more looking forward to being in my new place.


https://youtu.be/PzbxzFW6rBU

[nathan_s]

Just got some great news! My prop has shipped from Airmaster. I had been advised it was looking like it would be next spring before it would arrive, but I guess some circumstances changed, and it is now on its way!

[Kitfox Pilot]

Just got some great news! My prop has shipped from Airmaster. I had been advised it was looking like it would be next spring before it would arrive, but I guess some circumstances changed, and it is now on its way!


Good to hear! Hopefully supplies will get back to normal on lots of items.

[nathan_s]

Airmaster prop arrived yesterday, and looks great! It'll be a while before I can mount it though.

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